Rotary striking hammer with tip-attached wear member



July 5, 1955 s, c, JENSEN 2,712,417

ROTARY STRIKING HAMMER WITH TIP-ATTACHED WEAR MEMBER Filed April 4, 1952 Fig. 2. 0

I N VEN TOR.

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' rates atent @iifice 2,712,417 Patented July 5, 1955 RGTARY STRIKING HAIWMER WITH TE-ATTACHED WEAR mi /[BER Sanning C. Hansen, Neola, Iowa Application April 1952, Serial No. 280,446

2 (Zlaims. ((Ii. 24i197) This invention relates to hammermills and more particularly it is an object of the invention to provide a tip for attachment to the end of a hammer of such a mill which is adapted to be self-sharpening.

It is well known that the outer ends or the tips of the hammermills receive the majority of the wear and do the majority of the work. This is true because of the centrifugal force throwing the material being chopped to the outer ends of the hammers. It is especially dificult and costly to sharpen and replace the tips of such hammers.

it is, therefore, an object of this invention to provide a tip for a hammermill which is self-sharpening, the construction of the tip being such that its outer sides are harder than the interior thereof whereby the outer sides stand out sharply after the interior has worn away to provide cutting edges on each side or edge of the tip separated by a concave interior surface.

Another object of this invention is to provide a tip as described which is of substantially a U-shape so that four cutting edges are presented to the work at each hammertip.

Another object of the invention is to provide a hammer assembly including an arm particularly designed for receiving the tip of this invention.

Another object of the invention is to provide a device for the purpose described which is sturdy and durable in construction, reliable and efiicient in operation, and relatively' simple and inexpensive to manufacture, assemble and utilize.

Other and still further objects and advantages of the invention will become apparent from the following detailed description of a preferred embodiment thereof.

In the drawings:

Figure l is a perspective view of the hammer assembly of this invention.

Figure 2 is a view-in-section taken along the line 2-2 of Figure 1.

Figure 3 is an end view of the tip portion of the assembly of Figure 1, shown as it appears after the interior thereof has been worn away in use leaving the harder edges standing out from concave interior surfaces.

Figure 4 is a side elevation of the tip of Figure 3 showing the irregular fashion in which the leading edge of the tip wears away, the head of a securing screw being shown in Figure 4 but not in Figure 3.

Figure 5 is a top plan view of the worn tip of Figure 4, the screw not being shown.

The hammer assembly of this invention includes a hammer proper generally indicated at 16 in Figure l. The hammer is generally of an elongated rectangular shape.

The hammer 10 is preferably of laminated construction having two fiat half portions 12 and 14 disposed side-by-side and secured together by a plug 16 which latter is very tightly held by the walls of two holes 20 which latter extend through the two half portions 12 and 14 of the hammer portion 10.

The two portions 12 and 14 are provided with aligned bores 24 extending transversely therethrough at one end thereof. The other end of one of the half portions 12 of the hammer is longer than the other half portion 14 for receiving a tip generally indicated at 30.

The tip is preferably of a U-shape in frontal elevation as best seen in Figure 3, the arm portions 32 and 34 of the tip being disposed in parallelism with each other. One of the arm portions 34 can be longer than the opposite arm portion 32 if desired.

The arm portions 32 and 34 are provided with aligned apertures therethrough for receiving a screw 44. One of the arms 34 is provided with a wider outer end for countersinking the head of the screw 44 beneath the outer surface thereof in use.

The opposite arm 32 is provided with threads around the Wall of its aperture 40 for threadedly receiving the screw 44.

The overlapping end of the portion 12 of the hammer i0 is provided with a passageway therethrough for receiving the bolt 56. If desired, the walls of the passageway 60 can be inclined for receiving a portion of a head of the screw 44 as best seen in Figure 2.

The outer sides of the tip 30 are scientifically hardened in any desired manner as, for instance, by the method known as case-hardening.

The center of the tip 30 is permitted to remain softer than the outer sides.

In operation, the constant striking of the hammer will cause the softer interior 76 of the tip 39 to wear away leaving a concave leading surface. The outer sides of the tip will remain because of their hardness and will form cutting edges as indicated at 86.

Further wearing of the tip will continually re-sharpen the leading edge thereof by wearing away the center and leaving the sides 80.

As thus seen in Figure 4, the leading edge of the tip 30 will become worn away in an irregular fashion in side elevation as shown at and this will notaffect the continual wearing away of the center 70 of the tip.

This invention has provided a self-sharpening tip for hammermills which is adapted to greatly reduce the cost of operation of such machines while greatly increasing the efiiciency thereof, and has also provided a hammer construction particularly adapted for use with the tip of this invention.

From the foregoing description it is thought to be obvious that a hammermill tip constructed in accordance with my invention is particularly well adapted for use by reason of the convenience and facility with which it may be assembled and operated, and it will also be obvious that my invention is susceptible of some change and modification without departing from the principles and spirit thereof, and for this reason I do not wish to be understood as limiting myself to the precise arrangement and formation of the several parts therein shown in carrying out my invention in practice, except as claimed.

I claim:

1. A hammer assembly comprising: an elongated hammer said hammer being thinner at one end than along the remainder thereof, said hammer having a bore therethrough at the thicker end thereof, said hammer being of laminated construction having two portions disposed sideby-side and secured to each other; a tip for attachment to the end of said hammer, said tip comprising a member having its outer sides of harder composition than the interior thereof, said member being of substantially a U shape in side elevation, the inner sides of the arms of said member each being flat; a screw disposed extending through said tip and through said narrow end of said hammer, said screw having a head countersunk in said tip.

2. A hammer assembly comprising: an elongated 3 hammer, said hammer being thinner at one end than along the remainder thereof, said hammer having a bore therethrough at the thicker end thereof, said hammer being of laminated construction having two portions disposed side-by-side and secured to each other; a tip for attach ment to the end of said hammer, said tip comprising a member having its outer sides of harder composition than the interior thereof, said member being of substantially a U shape in side elevation, the inner sides of the arms of said member each being flat, said tip member being of a uniform thickness on each of its sides and in its outer end; a screw disposed extending through said tip and through said narrow end of said hammer, said screw having a head countersunk in said tip.

UNITED STATES PATENTS Wald Feb. 1, Lucas May 19, Poleske July 24, Shelton Nov. 27, Bukacek July 23, Tankersley Apr. 8, Lanter Aug. 2, Ball July 8,

FOREIGN PATENTS Germany May 30, Germany Sept. 27, Germany Aug. 3,

Germany J an. 11, 

